1. Field of Invention
The present invention relates to a tank system and a decompression method for the tank system.
2. Description of Related Art
A tank for storing gas or liquid contents under high-pressure is equipped with a safety valve to prevent the tank from rupturing. Examples of safety valves known in the art include a spring type safety valve to prevent pressure in the tank from exceeding an allowable pressure, and a fusible-plug type safety valve to release the tank contents to the atmosphere before the temperature of the tank exceeds an allowable temperature.
Proposed methods for reducing the pressure in a tank before the temperature of the tank exceeds an allowable temperature include methods using an improved fusible-plug type safety valve and a valve other than a fusible-plug type safety valve (for example, see Japanese Patent Application Publication No. JP-A-2005-69417, Japanese Utility Model Application Publication No. JP-U-26-6447, Japanese Patent Application Publication No. JP-A-2001-283343, and Japanese Patent Application Publication No. JP-A-2005-315294).
However, according to the related art, the temperature of the tank is detected only at one location; thus, when a local temperature increase occurs in the high-pressure tank, heat due to the local temperature increase may not be transmitted to the location where the temperature of the tank is detected due to the influence of the outside air temperature or the like, so that the tank may not be decompressed.